Chess is 99% tactics. If this celebrated observation is true for the master, how much more so for beginners and casual players! If you want to win more games, nothing works better than training combinations.
There are two types of books on tactics, those that introduce the concepts followed by some examples, and workbooks that contain numerous exercises.
Chess masters and trainers Franco Masetti and Roberto Messa have done both: they explain the basic tactical ideas AND provide an enormous amount of exercises for each different theme. Masetti and Messa have created a great first tactics book. It teaches you how to:
identify weak spots in the position of your opponent
recognize patterns of combinations
1001 Chess Exercises for Beginners can also be used as a course text book, because only the most didactically productive exercises have been used.